Adrenal Dysfunction/ Adrenal Medulla Flashcards

1
Q

Primary Adrenocortical Insufficiency (Addison Disease) is characterized by what

A

defect within adrenal gland

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2
Q

Primary Adrenocortical Insufficiency (Addison Disease) is cased by what

A

destruction of gland by tuberculosis, metastatic tumor
an autoimmune disorder
inborn errors of steroid hormone synthesis

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3
Q

Clinical Features of Primary Adrenocortical Insufficiency (Addison Disease) are

A

aldosterone deficiency
cortisol deficiency
androgen deficiency

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4
Q

consequences of aldosterone deficiency are

A

decreased renal absorption of Na+ (hyponatremia and polyuria)
extracellular fluid depletion (reduced plasma volume, hypotension, dehydration)
hyperkalemia

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5
Q

consequences of cortisol deficiency

A
inability to handle stress
hypoglycemia when stressed or fasting
weakness and fatigue
hypotension
decreased appetite and weight loss
anemia
hyperpigmentation
GI discomfort, nausea and occasional vomiting
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6
Q

consequences of androgen deficiency

A

loss of pub and axillary hair in females

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7
Q

Secondary Adrenocortical Insufficiency is associated with what

A

insufficient production of ACTH

insufficient production of renin

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8
Q

clinical supraphysiological doses of synthetic glucocorticoids cause what (and how)

A

Secondary Adrenocortical Insufficiency associated with ACTH

surpasses the hypothalamic-pituitary axis and depression of ACTH leads to adrenal atrophy

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9
Q

pseudohypoaldosteronism is cased by what

A

loss of function mutant in the mineralocorticoid receptor

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10
Q

pseudohypoaldosteronism is characterized by what

A

severe salt wasting in neonate
hyperkalemia
metabolic acidosis
failure to respond to treatment with mineralocorticoids

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11
Q

cushing syndrome is characterized by what

A

excessive cortisol secretion

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12
Q

major causes of cushing syndrome are?

A

injection of pharmacological doses of glucocorticoids
excessive secretion of ACTH by pituitary (Cushing’s Disease)
ectopic, non-endocrine, ACTH secreting tumors
tumors of adrenal cortex

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13
Q

patients with cushing syndrome have what clinical facial feature

A

moon face with acne

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14
Q

clinical features of cushing syndrome are?

A
obesity
hypertension
glucose intolerance
hirsutism
amenorrhea
purple cutaneous striae
bruise easy
osteoporosis
acne
poor wound healing
mental effects
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15
Q

what are the mental effects related to cushings

A

personality changes
insomnia
depression

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16
Q

poor wound healing seen in bushings is due to the inhibitor effects of cortisol on what

A
production of mediators of inflammation
production of chemotaxic and mitogenic mediators
fibroblast proliferation
collagen biosynthesis
circulating levels of WBCs
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17
Q

Primary aldosteronism (Conn Syndrome) is caused by what?

A

autonomous secretion of aldosterone, usually by ademona arising from zona glomerulosa

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18
Q

Primary aldosteronism (Conn Syndrome) symtoms are

A

mild hypertension
hypokalemia
metabolic alkalosis
low plasma renin

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19
Q

in patients with conn syndrome plasma renin levels are what?

A

depressed (as a result of expanded extracellular volume)

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20
Q

secondary aldosteronism is cased by what

A

inappropriate activation of renin-angiotensin system

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21
Q

Congenital Adrenal Hyperplasia (CAH) refers to what

A

group of genetically transmitted enzymatic deficiencies in the biosynthesis pathway for adrenal steroids

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22
Q

hyperplasia results when?

A

deficiency in biosynthetic pathway for cortisol

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23
Q

deficiency in biosynthetic pathway for cortisol result in what

A

decrease in negative feedback inhibition resulting in rise in ACTH secretion

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24
Q

what actually induces the hyperplasia of the adrenal gland

A

tropic effect of ACTH

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25
in hyperplasia there is a build up of what
steroid intermediates directly behind the enzymatic block
26
most frequent block in congenital adrenal hyperplasia is in what
21-hydroxylase enzyme
27
21-hydroxylase enzyme block is characterized by what
virilizing syndrome due to excess androgen production in the adrenal and non-adrenal tissues from pre block intermediates
28
in females 21-hydroxylase enzyme block leads to what
fusion of labia and clitoral hypertrophy if exposure to androgens occurs before 12 weeks exposure after 12 weeks leads to clitoral hypertrophy alone
29
in males 21-hydroxylase enzyme block leads to what
increase in somatic growth premature closure of epiphyseal plate early maturation of genitalia development of secondary sexual characteristics
30
adrenal medulla contains what type of cells
modified postganglionic cells (chromaffin cells)
31
chromaffin cells secrete what and into what
catecholamines directly into the blood stream
32
chromaffin cells are innervated by what fibers
cholinergic preganglionic fibers
33
what are the principle catecholamates released from the adrenal medulla
epinephrine and norepinephrine
34
aprox 80% of chromaffin cells secrete what
epinephrine
35
the only source of circulating epinephrine is where
adrenal gland
36
most norepinephrine in the blood is released from where
nerve terminals
37
chatecholamine release by adrenal medulla is an important part in acute response to what?
stress
38
catecholamine biosynthesis involves the stepwise modification of what to what
tyrosine to dopamine
39
the first step of converting tyrosine to dopamine is what
tyrosine to dihydroxyphenylalanine (DOPA) by tyrosine hydroxylase
40
what is the rate limiting step in the conversion of tyrosine to dopamine
tyrosine to dihydroxyphenylalanine (DOPA) by tyrosine hydroxylase
41
what is the transporter that brings dopamine into the chromaffin granule
VMAT
42
in the chromaffin granule what happens to dopamine
converted to norepinephrine
43
what happens to norepinephrine in cromaffin granule
exits granule via facilitated diffusion converted to epinephrine in cytoplams
44
norepi becomes epi how
phenylthanolamine-N-methyltransferase (PNMT)
45
what happens to epinephrine created in cytoplasm of chromaffin cells
transported back into chromaffin granule via VMAT where it is stored until release
46
catecholamines are stored in chromaffin granules in a complex with what
ATP, Ca2+, and chromogranin
47
about 50% of circulating catecholamine pool is loosely bound to what?
albumin
48
the adrenal medulla is usually activated in concert with what
rest of sympathetic nervous system
49
what is released from preganglionic fibers to promote the release of catecholamines that are stored in chromaffin granules
acetylcholine
50
acetyl choline promotes transcription of what enzyme
tyrosine hydroxylase
51
what connects adrenal medulla and cortex
portal system
52
cortisol promotes what (in terms of catecholamines)
promotes conversion of norepinephrine to epinephrine | induces phenylethanolamine-N-methyltransferase (PNMT)
53
cortisol prevents chromaffin cells from what?
developing into postganglionic neurons
54
catecholamine-degrading enzymes (name them
``` monoamine oxidase (MAO) catecholamine-o-methyltransferase (COMT) ```
55
what happens to NE released by nerve terminals
either repackaged into secretory granules or degraded by MAO and COMT
56
tissues degrade catecholamines predominantly how?
COMT-mediated methylation
57
major classes of metabolites resulting from the inactivation of catecholamines (name them)
metanephrines | vanillylmandelic acid
58
useful measure of total catecholamine production
urinary levels of metanephrines and vanillylmandelic acid
59
adrenal medulla releases catecholamines into the blood in response to what
sympathetic activation caused by fright, danger, trauma, hemorrhage, hypoglycemia, vigorous exercise
60
alpha 1 adrenergic receptors work via what pathway
Gd: IP3, Ca2+, DAG
61
alpha 2 adrenergic receptors work via what pathway
Gi: decreasing cAMP
62
then beta adrenergic receptors work via what pathway
Gs: cAMP
63
Pheochromocytomas (what are they)
catecholamine-producing tumors of chromaffin cells of the adrenal medulla or extra-adrenal ganglia
64
Pheochromocytomas (clinical features)
hypertension, tachycardia, tremors, sweating, anxiety, headache